November 2015SST Son of Ampzilla II Power Amplifier And Thoebe II PreamplifierA remarkable sound with excellent soundscape.Review By Ron Nagle

Spread
Spectrum Technologies (SST) Son of Ampzilla II power amplifier and Thoebe II
preamplifier ($3500 each) reviewed here are a continued effort to improve on the
original designs by audio engineer James Bongiorno. There was a time when I knew
the man. His aura was different, like his appearance, sometimes red, sometimes
he was, as I remember, green. He could make a box of wires talk and he could
make that box of wires sing. He could play the piano and somewhere his CD is
still buried in my stacks. Alas he is no more now due to passing on January 10,
2013, and gone with him is his rainbow colored clothing. He was James Bongiorno
audio engineer, entrepreneur extraordinaire. You can trace his professional life
through Marantz, Dynaco, SAE, Sumo Electric, GAS (Great American Sound Company),
and lastly to our test subjects manufacturer, Spread Spectrum Technologies.
Before Jim's passing he formed a partnership with EJ Sarmento of
wyred4sound.com. As of this report wyerd4 sound has purchased the SST company in
full. It was EJ Sarmento who streamlined and improved the quality control and
the manufacturing process that James Bongiorno began.

Years ago in Las Vegas I went to a dinner at the
Rio hotels, All American Barand Grill with some friends. At this dinner there
was JB and another acclaimed audio innovator, Bob Carver. During dinner they
chatted as friends would reminiscing about old times. With one ear wide I
shamelessly eves dropped on bits of their conversation, at one point they joked
about pulling late nights winding transformer coils with an electric drill.
Remembering JB I could not help but reflect on his somewhat closed continence.
It was as though he weighed everything I said. But of course all that is very
subjective. Intimidated? Yes very possibly, after all his life represented so
many things I had not done.

Thoebe II PreamplifierLet us start upfront with the smaller signal
preamplifier. My reasoning is that its character will season the sound of
whatever flows through it and pass that on to the power amplifier. First we need
to get the obligatory list of nuts and bolts hardware out of the way! You can
order the Thoebe II with four different configurations. First configuration
would be standard as a line amplifier with a Class A headphone output for $3500.
A second option would be to add an ESS Sabre (9018) 32-bit DAC chip that
supports 32-bit/384kHz sample rates including DSD 64/128 and that will be an
additional $500, thus bringing the overall price to $4000. The third option
would be to just add a Class A moving magnet (MM) phono stage, again the total
asking price is $4000. Last configuration includes both the DAC and the Phono
stage for a grand total of $4250. This is the way the review sample was sent to
me as it had all the options.

The Control PanelThe review sample front panel is black in color and somewhat
non-standard in its layout. The aluminum face plate is 17.5 inches wide and 0.25" thick. The chassis cover is made of steel and measures,
14.675" deep
and is 4.175" high. On the left side are not one, but two 1/4" inch
headphone jacks. The left side jack is a standard live output whereas the right
side jack will mute the preamplifier output so the speakers are turned off. Side
by side under a Green florescent display, is an array of ten small black push
buttons. In my system the buttons are hard to see from my chair. First on the
left is a Standby/Power button, Next are two push buttons with white up and down
arrow symbols silk screened under them. They allow you to scroll/step through
the available inputs so you can select your music source. As you do this the
Green display changes to indicate which input is active. Positioned directly
under the display is the remote control receiver.

Continuing on the right there are seven additional push
buttons, they are: Bass and Treble (adjustment 1 to 5), Balance (range 1 to10),
Phase (0 and 180), Gain (high or low) Dim (Display 3 choices, normal, dim, off)
and Mute. Note: The phase control inverts all of the inputs going into the
Thoebe II. These push button functions should be familiar to most audiophiles.
Last but no least is the dual function front panel volume control knob. The
volume control is different in that it has no detents therefor no starting point
and no stop to let you know it is at maximum volume. The volume control spins
very freely in either direction and so it seems to function more like a digital
encoder. Now everything on the front panel is duplicated by the functions of the
remote control. Unusually the remote control is not supplied with the
preamplifier. But it is available as a $175 option.

Non-intuitive, the front panel volume control knob serves two
purposes. As you should expect it will increase and decrease the speakers
loudness. But it is also used to adjust other functions. As an example let us
say you want to shift the center image between your speakers more to the left of
center. First depress the Balance button. The display changes to show what looks
like a closed parenthesis symbol. To shift the audio image more to the left you
rotate the volume control knob counter-clockwise.
As you so the displays numerical readout (Starts blank no number) will increase
up to a maximum of #10. Conversely you would move the volume control clockwise
to shift the center image to the right. If you would like to adjust the
bass level or reset the amount of treble you would first press either the Bass
or Treble button on the front panel (the display has no numbers). After you make
your selection you can use the volume control knob to increase or decrease the
Bass or Treble up to a maximum numerical level of #5. If you decrease Treble or
Bass the (-) minus symbol will be a prefix before the number setting. Increasing
a setting will show a (+) plus prefix before the numerical display.

Or maybe in plain speak it is far easier to say, choose a
function and you can adjust the amount with a Clockwise or Counterclockwise
twist of the volume control. Every adjustment you dial in will time out after 8
seconds and the display will revert to the last source you were listening to.
Also a very nice feature is the initial power up sequence. It always begins with
the preamplifier in a quiet standby mode. There are two remaining functions they
are Phase and Gain. Previously I have seen digital to analogue converters (DACs)
and CD players that had a phase flipping control. These were primarily because
some CD's were (rumored) to be out of phase. Incidentally I have found phase
inversion most useful with self powered subwoofers. Last we take a look at that
Gain button controlling thing. I assume it's primary purpose has to do with the
Moving Magnet Phono amplifier in the Thoebe. But additionally it may be used to
match other manufacturers' power amplifiers. This seems likely because both of
these functions are not device specific because they affect all of the input
sources equally. Finally we have reached the end of the button flipping
functions!

Thoebe's Rear EndHere is when we look at Thoebe's gray back panel. There are
three stereo pairs iof RCA input connections at the rear of the preamplifier and one pair of XLR
inputs, so that's a total of 4 analog inputs. The first RCA pair on the left
side is on this review sample configured as the optional phono amplifier
connection. Otherwise it would be used as RCA #4 and it will serve for any line
level input. Next, lined up side by side there are three pairs of RCA jacks. They
are designated as RCA #1 to #3 as shown by the front panel display. I know they
do this to provide flexibility but. Call me old fashioned, but I would prefer
that they were labeled more conventionally as Tuner, Tape, etc: So that the
front panel display would tell me in words what was plugged into these three RCA
connections. In my case I do have the word phono amplifier appear in what might
otherwise be called RCA #4. All the other front panel displays are spelled out
by their active connections, such as the three digital rear panel inputs:
Coax, TOS, USB including the Phono, XLR. The XLR input was connected to my Music
Hall DAC 25.3. The XLR output was the connection to the Ampzilla II Power
Amplifier. Oh! and of course there is an IEC power cord socket in back.

The Son OfAmpzilla IIDon't panic, it's not really organic! I believe this power
amplifier is genealogically speaking number five in the Zilla line. Of course
the original Amp Zilla-Killa nut crushing power amplifier (is still in
production as a monoblock) was James's first born child. This may be a smaller
edition and great great grandson amplifier but still it is an imposing chunk of
iron. Dimensions are 9.875" X 17.25" X 5.675 (LxWxH) and the SST Ampzilla
weights 40lbs. Power output is rated at 220 wpc into 8 Ohms. Again, shoot me
Editor if I didn't tell everyone the way its laid out. (Editor's
Note: I've been busy editing this to sound more fluid... and think I failed
miserably at it due to flat-tire English.)

Like the Thoebe II the power amplifier front is black in
color. The front panel has left and right channel power status LED diodes. There
are three grouped horizontally on the left side and three on the right. The
center red Led is labeled Status, this indicates normal operation. On either
side straddling the Status LED are two more LED's. The left side is labeled B+
the right side is labeled B-. This refers to the Plus or Minus amplifiers 'B" power rails. If either Led is illuminated chances are one of the power
rails fuses has blown/opened. The same is true for the other power status LED
diodes on the right side. Logically they can quickly tell us the Left and Right
channels operational status. Dead center is the round power button, and directly
above it is a small red LED labeled Thermal. And that may be very useful
because, dear reader, this amplifier cries Ventilate
Me because it runs mucho caliente.
Let us look at the layout of the power pushing rear panel.

In back I find there are two small ergonomic features that
should/needs be more user friendly. O.K. it's nothing that will affect the
amplifier performance. However, this is a 'Whats up with that" observation.
As you would expect on either side are a pair of five-way speaker cable binding
posts for the left and right channels. Question one: Why are they placed
close together and arranged vertically one above the other. My Kimber 12TC
speaker cables have locking WBT banana plugs that are laying on top of each
other. Consequently I wedged a thin piece of cardboard between the WBT plugs,
just for my peace of mind. Most amplifiers have speaker cable binding posts
logically laid out horizontally next to each other because cables hang down. Let's look at a very nice feature and this is the provision made available to
use either unbalanced RCA or balanced XLR preamplifier input connections. The
manufacturer tells us the Ampzilla II circuit is completely balanced from input
to output. These two types of preamplifier input connections are grouped at the
top center of the rear panel. (Editor's
Note: Are we there yet? Oh, guess not.)

The XLR connections are positioned on either side of the
RCA jacks like this: --> XLR RCA-RCA XLR. Question two: Directly in between
these connections is another squintingly small black push button located on the
power amplifiers dark gray back panel. It is used to select between either of
the two preamplifier inputs. This RCA/XLR selection switch on the back of the
amplifier only grounds the XLR input connection. It doesn't actually switch
between the two connection types. So either type of connection will work, but if
the switch isn't set correctly, the amp will sound noisy and the gain will be
off. True you shouldn't need to use it very often. But, if it was a small toggle
type switch all you would need to do is look at it to see what position it was
in.

MethodologyLogic dictates that each of the SST preamplifiers and power
amplifiers first be evaluated separately and then combined as a system. My
reference system amplification at this time is solid-state, with the system
being cycled on via a single button from my APC (American Power Company) S15
power conditioner. There is a Parasound P5 preamp feeding a Sanders ESL muscle
amplifier. Cables are Kimber 12TC feeding my two-way Arum Cantus SES speakers on
24" stands. Mark & Daniel Omni Harmonizers sitting on top of the speakers.
The Harmonizers are really add on Oskar Heil tweeters that reach out to 40kHz.
Thus the first order of business is to run the SST Thoebe preamplifier for about
six hours then swap out my Parasound P5 preamplifier and slot in the Thoebe II.
Before I get to my ‘what it sounds like' part, let me share my very first
impressions. The SST preamp is quite hefty in weight and feels more like a power
amplifier built into a smaller preamplifiers form factor. I have a Marantz 8400
CD, DVD, SACD player feeding an outboard Music Hall upsampling DAC 25.3. So I
have connected the Music Hall DAC directly to the Thoebe II preamplifier via
balanced XLR cables. The Marantz universal CD deck is connected via optical TosLink.

And now, finally, let me tell you about Thoebe's voice as it
is time to play music. SST's Thoebe II preamplifier has a warmer presentation
than my Parasound P5. Thoebe II presents instrumental sonorities on a more
expansive and deeper center stage and, for me, am very much into music and
imaging so this is paramount for me. All the hardware bells and buttons and
whistles are only a means to an end. So I dim the lights and let the walls
recede, to a broad liquid soundscape and there I can reside quite contented.

SST Ampzilla IILet's make a system from these two halves. We remove the
Sanders muscle amplifier and replace it with the $3500 Son of Ampzilla II. Is
this a match made in heaven? Well I haven't been to heaven, yet it certainly
compliments the preamplifier with even more hollow state tube dimensionality.
Especially at the low end of the spectrum were the bass provides a fundamental
foundation to our stage. Combining the Thoebe II and the Son of Ampzilla II
forms an synergistic combination that presents a lifelike flesh and blood
realism. Not too fuzzy warm and not too cool either. With a variety of music
played through this system, it produces music that sounds very approachable. The
power part of this pairing adds more depth and dimensionality exceeding the much
more powerful Sanders amplifier. Let's get specific and cue up The Absolute Sound Reference CD [STD Digital-6111142]. This
is a compilation of 12 different music samples. Track #9 titled 'Works
for Harpsichord" by J.S. Bach is the perfect test medium for transient speed
and attack. Listening the rapid tempo of this composition and the lingering
sustain causes every reverberant note to hang in space long enough so that the
following notes reverberant sounds overlap. At one point the rear soundstage
reverberated with an echo that built up to mimic something similar to a humming
sound. I had never experienced this effect with any other system. It was a
continuance painted on a remarkably deep center stage. The Ampzilla II turns out
to complement all the flavors and nuance painted by the Thoebe II. Via two
different mid-priced sets of headphones, track #9 was clean and clear yet could
not quite match the ability of the Thoebe II preamplifier to delineate subtle
details.

DenouementLet us try what has to be the acid test as at this point
everything in the SST system comes into play. What conclusions can, and should
be made, are now clearly evident now. So at this juncture we need to feed Thoebe
II and the Ampzilla II some really small millivolts. If done correctly, there
will be nothing extraneous riding the musical soundscape. Of my six cartridges
the Moving Magnet Shure V-15 type 3 V-MR with a 3.5 mV output should be an ideal
match. During the recent THE Show Newport I purchased Crystal Visions' The
Best Of Stevie NicksGreatest Hits
[Reprize-1000363-2], which is a two LP album on clear vinyl mastered by Stan
Ricker. Color me very happy to find the SST preamplifier was dead quite with the
volume cranked up with the tonearm and cartridge lifted up off of the record.
Very highly qualified people were involved in making this recording, with a very
mixed outcome. One of my favorite songs, "Dreams," was backed up by
something called "Deep Dish". In this version the tempo was twice as fast as
the original Fleetwood Mac
recording. The bass and the multi-track mix effects simply overpowered Stevie
Nicks lead voice. On the track "Landslide" it is Stevie accompanied by the
Melbourne Symphony. Wow! What you hear is a vast soundscape pushing the wall
behind my loudspeakers out into the street. Massed violins with a swirling sound
deep center threading through and riding above the stage. You might think this
confused multi-element recording is a bad thing, yet this tells a powerful story
as it requires a very quiet amplifier with superior resolving power to pick
apart the rapidly shifting image floating between your speakers.

Last WordThe combination of the Thoebe II and the Son of Ampzilla II
encapsulates a very unique sound. It reproduces music like a hybridization cross
between a Class A solid-state amplifier with the harmonic structure of
ultra-linear vacuum tubes. It manages to capture some of the best traits of each
design yet it stands alone. If like me you love to wander in a field of sound,
then let this be your doorway.